Thirty Years of Experience of Acute Flaccid Paralysis Surveillance for Polio - China, 1993-2022

Hong Yang; Ning Wen; Chunxiang Fan; Fuzhen Wang; Yong Zhang; Lei Cao; Shuangli Zhu; Lixin Hao; Dongmei Yan; Lei Wang; Quanwei Song; Miao Wang; Yifan Song; Chao Ma; Zhijie An; Lance E Rodewald; Huaqing Wang; Zundong Yin

doi:10.46234/ccdcw2024.065

Thirty Years of Experience of Acute Flaccid Paralysis Surveillance for Polio - China, 1993-2022

China CDC Wkly. 2024 Apr 19;6(16):344-349. doi: 10.46234/ccdcw2024.065.

Authors

Hong Yang^{1

2}, Ning Wen^{1

2}, Chunxiang Fan^{1

2}, Fuzhen Wang^{1

2}, Yong Zhang^{1

3}, Lei Cao^{1

2}, Shuangli Zhu^{1

3}, Lixin Hao^{1

2}, Dongmei Yan^{1

3}, Lei Wang^{1

2}, Quanwei Song^{1

2}, Miao Wang^{1

2}, Yifan Song^{1

2}, Chao Ma^{1

2}, Zhijie An^{1

2}, Lance E Rodewald^{1

2}, Huaqing Wang^{1

2}, Zundong Yin^{1

2}

Affiliations

¹ National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases (NITFID), Beijing, China.
² National Immunization Program, Chinese Center for Disease Control and Prevention, Beijing, China.
³ Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.

Abstract

Introduction: Detecting poliovirus infections proves to be highly challenging due to their asymptomatic nature and infectious potential, highlighting the crucial importance of effective detection methods in the context of polio eradication efforts. In many countries, including China, the primary approach for identifying polio outbreaks has been through acute flaccid paralysis (AFP) surveillance. In this study, we conducted an evaluation spanning three decades (1993-2022) to assess the effectiveness of AFP surveillance in China.

Methods: Data on all AFP cases identified since 1993 and national-level AFP surveillance system quality indicators aligned with the World Health Organization (WHO) standards were collected for analysis. The quality indicators assess surveillance sensitivity, completeness, timeliness of detection notification, case investigation, and laboratory workup. Surveillance sensitivity is determined by the non-polio AFP (NPAFP) detection rate among children under 15 years of age.

Results: Between 1993 and 2022, a total of 150,779 AFP cases were identified and reported. Within this pool, surveillance identified 95 cases of wild poliovirus (WPV) and 24 cases due to vaccine-derived poliovirus. From 1995 onwards, the detection rate of NPAFP cases consistently adhered to the WHO and national standards of ≥1 case per 100,000, falling between 1.38 and 2.76. Starting in 1997, all timeliness indicators consistently achieved the criteria of 80%, apart from the consistency in meeting standards set for the rate of positive specimens sent to the national laboratory.

Conclusions: AFP surveillance has been instrumental in China's accomplishment of maintaining a polio-free status. The ongoing adherence to key performance indicators, ensuring sensitivity and prompt specimen collection, demonstrates that AFP surveillance is proficient in detecting poliovirus in China. As we move into the post-eradication phase, AFP surveillance remains crucial for the sustained absence of polioviruses in the long term.

Keywords: Acute Flaccid Paralysis; Polio; Surveillance.

Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2024.

Grants and funding

Supported by the public health emergency response mechanism operated by the Chinese Center for Disease Control and Prevention (No. 102393220020010000017)